Jogger Tegwyn Jones discovered the teen’s body at around 8pm in a pedestrian underpass by the Foudry Brook and flagged down passing motorist Craig Tull who called 999.

During the second day of trial at Reading Crown Court jurors heard Akhter called friends asking for a lift shortly after Asha was killed.

John Price, prosecuting, said Akhter and friends drove to a BP petrol station in Twyford where he bought a petrol can and filled it with just under a litre of petrol. He then ordered his friends to stop along a country lane where he set fire to a change of clothes and a mobile phone in a rucksack.

While in the BMW car driven by pal Kasam Zaman, Akhter admitted killing his ex-girlfriend, the court heard.

Giving evidence, friend Sikander Khan, who was also in the car, said: “I asked him what he was playing at. He said, ‘I can’t tell you’. Everyone was asking, we asked him again and he said, ‘If I tell you, you can’t tell anyone’. Then he said what he did. He just said, ‘I killed my girl’. He said, ‘I sliced her throat’.

Mr Khan continued: “He said he was looking for her phone in her bag or something. He said he got paranoid and ran away.”

Earlier the jury of six men and six women heard Akhter, whose street name was ‘Raks’ or ‘Rakz’, (sic) made more than 600 phone calls to her mobile in the two weeks leading up to her death.

Mr Price said: “Over 18 days he made 621 calls, that’s an average of 34 a day.”

The court also heard that between July 11 and 12, last year, shortly after the pair broke up, Akhter sent Asha 33 offensive text messages.

One of them read: “The start date is going to start now for your life being hell.” Another said: “I hope you go through hell and you die.”

Giving evidence, pathologist Dr Kenneth Shorrock explained the A-level student suffered “32 applications of the knife” to her neck and chest area including 27 deep cuts.

He explained one wound, about 5cm long, cut into vertebrae bone. He added it would have taken “severe force” to cut into bone.

“On the right side three of these wounds went into her voice box. Lower down another two cut into her windpipe,” he said.

He continued: “The left vertebral arteries had been cut. It is my view these wounds in the neck caused her death.”

Mr Shorrock also identified defence wounds found on her hands and old self-harm injuries on her left forearm.